I then got, “Audacity needs the file ‘avformat-55.dll’”. The instructions then said to open Audacity Library Preferences and FFmpeg Library “Locate”.

Move that into a desired permanent location and unzip it by : “Extract All…”, confirm that the target directory is appropriate, and click “Extract”. says, “The Audacity(r) QA Team suggests users download the ZIP version”, clicking on “libmp3lame-win-3.99.3.zip”.

Try installing FFmpeg.” The PATH on both machines includes ~“ffmpeg/bin”. When I try to File > Open a *.MOV file, both say, “Audacity did not recognize the type of file ‘…MOV’. I have “ffmpeg version N-89674 … Built w gcc 7.2.0” installed on a Windows 7 computer and “ffmpeg version N-93298 … Built w gcc 8.2.1” installed on a different machine running Windows 10. Installing and updating Audacity on Windows#Installing the FFmpeg Import/Export Library on Windows says, “If you already have Audacity-compatible FFmpeg 2.2.x or 2.3.x shared libraries in the system PATH, Audacity will use those as long as you do not install FFmpeg from the links below and as long as you do not specify the FFmpeg you want Audacity to use in Libraries Preferences.”